What are proteins and why are they so important?

What are proteins made of?

As mentioned before, proteins are made up of a series of amino acids. These amino acids consist of carbon, oxygen, nitrogen, and sometimes sulfur molecules. There are numerous forms of amino acids that occur in nature. This makes each protein unique, as there are many possible combinations.

Proteins in the human body can contain a total of 22 different types of amino acids that are linked together in various ways. The longer connections are called peptides and the short chains of amino acids are called polypeptides.

Of the 22 amino acids, our bodies can produce 14 of them. These are called non-essential amino acids, of which 3 are semi-essential.

This means that our bodies can usually produce these 3 amino acids on their own, but in some cases not enough (such as in illness or conditions). The other 8 are the so-called essential amino acids that we must obtain through our diet.

Sources of protein

Many of our daily foods contain protein. Animal sources of protein include: meat, fish, poultry, eggs, cheese, and dairy products. Plant-based sources include soy products, legumes (beans, lentils, chickpeas), grains, nuts, seeds, and mushrooms.

Many people still think that plant-based proteins are not "complete" and do not contain all essential amino acids. However, this is not correct, and the difference between animal and plant-based protein sources lies in the fact that plant-based proteins often contain all amino acids but in a different composition and quantity than animal proteins.

Protein Quality

Animal proteins contain a wide range of essential and non-essential amino acids, while plant proteins often contain fewer essential amino acids. For example, grains contain a lot of methionine and little lysine, while (most) legumes are the opposite.

A few exceptions to this are pea protein, hemp seed, quinoa, and products made from soybeans (soy yogurt, soy milk, tofu, and tempeh). These are complete plant protein sources that, like meat and dairy, contain a high amount of essential amino acids. [1,2]

But also (a combination of) legumes (beans, lentils), whole grains, nuts, seeds, various vegetables, and mushrooms are rich in protein and provide all essential amino acids.

The important thing is to get enough protein and provide your body with all essential amino acids. Whether these amino acids come from animal or plant products doesn't matter.

How much protein does your body need?

The optimal daily amount of protein varies greatly per person but is between 1.0 gram and 1.8 grams of protein per kg of body weight for most people.

When you eat mostly plant-based, it is recommended to slightly increase your protein intake because many plant protein sources often also contain other (healthy!) nutrients (including fiber) that make them slightly less digestible.

Especially if you do strength training, it is best to increase your protein intake to about 1.6-2.0 grams of protein per kg.

Conclusion

In this article, we described what proteins are and that the body itself builds the necessary proteins from amino acids.

To be able to build all the necessary proteins, there must be a good balance of amino acids in the body, and it is important that your body gets all amino acids through varied food.

People often think of animal products like meat, fish, eggs, and dairy when they think of proteins, while there are plenty of plant protein sources that not only provide all amino acids but also many other healthy nutrients and no saturated fats and cholesterol.

The myth that plant proteins are not 'complete' and do not contain all necessary amino acids is not true. Animal proteins are not better than plant proteins and is a myth that we unfortunately still hear too often.

Eating enough proteins from, for example, legumes, quinoa, nuts, whole grains, or a plant protein shake ensures that your body gets enough proteins and has all amino acids to build a strong body and good health!